Simple project using 68K microprocessor

BobG a écrit :

No, 68K and 3 orders of magnitude make for 68. Maybe he forgot one because 69 is just what's needed to taste flip flaps.

But even then, why in the world would nayone need a CPU to test a few simple gates?

And if the point is to put together a small computer, then surely one would come up with a more recent 8bit CPU than the 6800 (or for that matter a more recent 16bit CPU than the 68000).

I'd use the old CPUs for some project, but that's because I'm loaded with them, taken out of old junk. Unless the school is supplying parts, and has lots of old parts, using the 68000 will be an impediment, apart from overkill.

Michael

Ask Teradyne or Advantest.

True, both are approaching museum-material status.

It's an equally valuable exercise for pedagological purposes whether the student uses a 68000 or an ARM or AVR. There is perhaps some small advantage in using an older, more orthogonal, architecture both for education and because nobody is likely going to be able to google the source code off the net.

Best regards, Spehro Pefhany

They need a CPU because solutions not using a CPU can be expected to score a big fat zero when handed in as project work for a course in microprocessors.

It's an excercise, nothing more. Step two after flashing an LED. Perhaps next term/semester they make something really difficult and exciting, but you gotta learn the tools, techniques and tricks somehow.

To the OP:

Apologies if this is overly basic, I'm assuming you just don't know where to start.

I assume the 68230 and the logic chips you will be testing are both running off the same voltage and have compatible IO levels, so can be connected directly. Connect the logic chip to power and to your 68230. Make a note of which pins connect to which. That is all the circuit you need (all the additional circuitry to do this anyway - you still need the 68k, clock source, power, programming interface...). You can now set the inputs of the logic and read its outputs all from software, by controlling the 68230's IO pins. I expect they chose testing logic chips precisely because they are so easy to interface with microcontrollers.

You need to provide known input (input to the logic, output from the

Of course, you real code will do that for all the gates on a logic chip, it'll handle a few different kinds of logic chip, there will be a bunch of code to handle your 7-segment displays...

Tim

Asking the students to use a 68000 and a 68230 is not any more pedagogical than asking them to program it in Cobol. Use the m68k architecture by all means - it is a solid architecture that is very much in use today - but use a realistic device such as a ColdFire. Very few embedded engineers design systems using pure processors and stand-alone timer peripheral chips, so there is little point in training people to do so. Start with something more practical, and then (if necessary) move to a more advanced design later.

Mebbe so, but I know of a local firm that makes a nice steady income out of selling 68000 trainer boards to the educational market.

Paul Burke

In message , dated Mon, 4 Sep 2006, Paul Burke writes

That says something not very good about the educational market.

That's a little different - programming the 68000 is perfectly suitable for educational purposes, since the architecture is very nice, there are plenty of tools, and the architecture is still widely used in new systems. It's asking students to design hardware boards based on the

Why is that a waste? Let those students worry a bit about addressing and bus conflicts, perhaps program a PLD for decoding too, instead of just connecting a led to an I/O pin on a microcontroller.

It all boils down to what you want to teach them, and whether the project matches their current level. Sure, working with a proper bus is instructive - but only if that's what the course is covering at the time. It sounds like in this case, the project is way over the heads of the students, so either they will fail to make any headway, or they will regurgitate someone else's design - either way, it's a waste of everyone's time. It is also such an artificial exercise (a powerful processor for testing a logic gate) that it is a poor example for students.

Having said that, if they want to make students use a processor (as distinct from a microcontroller), and learn the issues of bus decoding and everything else, then the 68000 is a good choice - the bus is well documented, there are some standard peripherals available, and (IIRC) it is available in DIP package.